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A study published in the Molecular Therapy journal detailed a therapy that prevented pregnant mice with Zika virus from transmitting it to their fetuses. It uses small extracellular vehicles (sESVs) to deliver the drug. Additionally, the drug could cross the blood-brain barrier and placenta. As a result, it reduced neurological damage in the fetus caused by the virus, such as brain shrinkage.

According to Zhiwei Wu, a lead study author from Nanjing University, the study showed that using targeted therapy through sESVs was better than traditional drugs, especially when treating brain infection. He adds that increasing the yield of sESVs and making sESVs that target various tissues will expand their application and delivery.

Zika virus crosses the blood-brain barrier

The Zika Virus pandemic has been a problem since it started in the Asia-pacific region between 2015 and 2017. It closes the blood-brain barrier, a group of blood vessels and tissues, to cause neurological abnormalities such as microcephaly. The virus also causes numerous neurological conditions.

The blood-brain barrier prevents harmful substances from entering the brain by bridging blood and the central nervous system (CNS). Few drugs cross this barrier to treat brain infection. However, they are usually toxic and do not pass effectively.

Wu adds that there is currently no medication or vaccine for the Zika virus. For this reason, they needed to create medication that is both safe and effectively tosses the placental and blood-brain barrier to treat the disease.

sESVs deliver oligonucleotides to the brain

Gene silencing therapies that use oligonucleotides have shown a lot of potential in clinical settings. Despite this, delivering oligonucleotides to cells is challenging. Using sESVs provides a solution as they are biodegradable, natural, and play and role in cell-to-cell communication. Many studies have shown that they could help deliver drugs that treat infectious diseases, cancer, and cardiovascular diseases.

The team engineering sESVs with rabies virus glycoproteins on their surface. They attached small interfering RNA from the Zika virus to them. The sESVs managed to cross both barriers preventing viral transition to the fetuses of mice.

A previous study also showed that sESVs could cross the blood-brain barrier to treat Parkinson’s disease. Wu states that their study adds another application for sESVs.